The present invention is directed to a railway locomotive traction motor and, in particular, to the friction support or sleeve bearing by which the traction motor is partially supported on the axle of the railway truck mounting the underside of the locomotive, and, in particular, the invention is directed to providing additional lubrication.
A conventional railway locomotive pinion-end (PE) traction-motor support bearing, such as that disclosed in U.S. Pat. No. 5,038,631, is shown in FIGS. 1 and 4, which FIGS. 1 and 4 show the half of the support bearing 10 that contains the window 12 for passing a lubricating wick. For best overall performance and life of the traction-motor support bearing, the load zones for loading the truck axle-journal should be centered. This is so in order that the lubricating wick (not shown) entering the interior of the bearing via the wick window or opening 12 lubricates all contacting surface-areas, which lubricating wick contacts the axle-journal through the window. In addition, both load zones should be contained within the total axial dimension of the wick if possible, again in order to ensure the best possible lubrication. Each traction-motor sleeve bearing has two load zones, an upper one and a lower one, and these tend to be heaviest around 25° from vertical because of commonly-used 25° gear-tooth pressure angle. Both load-contact patterns can be seen in the window half 10 of the PE bearing with the upper load pattern above the lubricator access-window and the lower load pattern below the window. Ideally, both upper and lower load contact-patterns should be centered at mid-length of the window, in order that the wick lubricator provides the best possible lubrication. Further, both load contact-patterns should be contained within the total axial dimension or limits of the wick lubricator if possible, again to ensure the best possible lubrication.
The lubricating wick of the conventional sleeve bearing shown in FIGS. 1 and 4 enters the bearing from the lubrication sump through a cast opening in the axle cap, which is aligned with the window or opening 12 in the bearing liner. This opening 12 is centered axially on the journal and the wick protrudes through this opening to contact the axle-journal at a position approximately 20°-30° below a horizontal line passing through the axle gear and pinion center lines. The sleeve bearing 10 also has a flange wick 16 for lubricating the flange-end 20.
The axial length of the preferred journal-to-liner contact area is defined by the axial length of the wick. The bearing liners are machined in such a way as to relieve the liners so that journal contact under normal loads remains in the wick-wetted axial area 14. In many traction motor support bearings, however, the envelope available for supporting the journal is significantly longer in the axial direction than the wick and the length of wetted area.
Pinion-end sleeve bearing load ratings are frequently limited by the axial length that can be reliably lubricated by the lubrication delivery system. If lubrication can be assured beyond the axial dispersion of conventional support bearings, that additional length may become useful for supporting the journal. By reducing the unit loading of the original journal and thereby increasing the load capacity, the criticality of other parameters affecting wear rate and reliability are lessened.
In applicants' copending application Ser. No. 11/178,937, filed Jul. 11, 2005, there has been disclosed the use of auxiliary wicks for increasing the wetted area in order to provide additional lubrication to the lateral areas beyond the width of the main central supply wick. These additional wicks are located one on either axial side of the central wick near the 6:00 location and are capable of communicating with the oil accumulated in the oil flinger grooves thereat to thereby take advantage of the oil-flinger rotating lift capability and lateral movement within the bearing lateral clearances for providing additional lubrication and for extending the envelope of the wetted area available for supporting the truck-axle journal in the axial direction. However, it has been found the felt pads constituting these auxiliary wicks may, under certain circumstances adhere to the face of the axle-journal, which may cause part of the auxiliary wick pad to be torn away during the axle-rotation. Moreover, it has been found that the additional lubrication provided by these auxiliary wicks may be better enhanced by more direct fluid communication with the respective flinger grooves which provides the lubricant supply wetting the pad faces of these auxiliary wicks. In addition, it has been found that a more optimal configuration of each auxiliary wick would be helpful in increasing the wick life.